Fix Travis build: run all tests for Fish 2 and 3.

.travis.yml

@@ -1,6 +1,14 @@
+env:
+    - FISH=release-2
+    - FISH=release-3
+
+matrix:
+    allow_failures:
+        - env: FISH=release-3
+
 sudo: required
 before_install:
-    - sudo add-apt-repository -y ppa:fish-shell/release-2
+    - sudo add-apt-repository -y ppa:fish-shell/${FISH}
     - sudo apt-get update
     - sudo apt-get -y install fish
     - curl -s "https://get.sdkman.io" | bash
@@ -12,12 +20,8 @@ install:
     - cp conf.d/* "${HOME}"/.config/fish/conf.d/
     - cp functions/* "${HOME}"/.config/fish/functions/
 
-jobs:
-  include:
-    - stage: Completion Tests
-      script: ruby test/completion.rb
-    - stage: General Wrapper Tests
-      script: fish test/wrapper.fish
-    - stage: Ticket-specific tests
-      script:
-        - bash -c "sdk install crash 1.3.0; sdk uninstall crash 1.3.0"; fish test/10_zombies_new.fish
+script:
+    - ruby test/completion.rb
+    - fish test/wrapper.fish
+    - bash -c "sdk install crash 1.3.0; sdk uninstall crash 1.3.0"; fish test/10_zombies_new.fish
+